Every version of every file in SharePoint Online counts against your tenant storage quota. A 500-user tenant left to run unchecked for two years can accumulate hundreds of thousands of redundant file versions - often five to ten times the actual working data size. The good news: most of that storage is recoverable within a few hours, without touching live files.
This guide walks through five concrete steps, ordered by typical impact, to reduce SharePoint Online storage quickly and safely.
What Counts Against Your SharePoint Storage Quota?
Before deleting anything, it helps to understand what Microsoft counts against your pooled tenant storage. The answer is broader than most admins expect.
- Current file versions - the live copy of every document, image, video, and page.
- Previous versions - every historical version retained in a document library. With a 500-version default limit, a single frequently-edited document can accumulate dozens of gigabytes in version history alone.
- First-stage recycle bin - files deleted by users but not yet permanently removed. Retained for up to 93 days.
- Deleted subsites - a deleted subsite goes straight to the second-stage (site collection) recycle bin and keeps counting until it is purged. Other items in the second-stage bin do not count against quota.
- Metadata and list attachments - typically a small fraction of total storage, but worth noting for large lists.
Version history and the first-stage recycle bin are the two biggest surprise contributors. A document revised 200 times may have 200 stored versions, each counted separately against your quota.
Step 1: Identify the Biggest Storage Consumers
Reducing storage without data is guesswork. Start by generating a storage report across your tenant to see which site collections, libraries, and individual files are responsible for the most space.
What to look for first
- Site collections over 50 GB - prime candidates for version cleanup
- Document libraries with high version counts (check average versions per file, not just total size)
- Individual files over 100 MB - images, videos, and PST files are common culprits
- Sites with no activity in the past 12 months - these may be safe to archive or delete
ShareMaster's Report Master exports a storage breakdown to Excel, showing for each library how much is current files and how much would be saved by trimming versions, plus a list of the largest files. That gives you a prioritised target list before you change anything.
The SharePoint admin centre alternative
The SharePoint admin centre shows per-site-collection storage under Sites > Active sites. It provides a useful high-level view but does not break down storage by version history or show file-level detail. It tells you which sites are large; it does not tell you why.
Step 2: Trim Version History in Bulk
Version trimming is almost always the single largest storage saving. Most documents only need the last 5 to 10 versions for any practical purpose, yet SharePoint's default 500-version limit means a busy library can accumulate thousands of versions per file over time.
Using PnP PowerShell, version trimming is possible - but slow. You iterate over every site, library, and file. For a tenant with tens of thousands of files, that script can run for days and is prone to throttling errors from the Microsoft 365 API.
ShareMaster's Version Trimmer does the same work graphically. Choose a library, or tick site collections across the tenant, set a retention rule such as "keep the last 10 versions", run the same settings as a report first to see what would be removed, then trim. It handles Microsoft 365 throttling automatically.
- Open ShareMaster and go to Optimize Storage (Space Master).
- Select Version Trimmer for a single library, or Bulk Version Trimmer to tick site collections across the tenant.
- Tick Retain some versions? and set the number of versions to retain (for example, 10). Optional rules cap versions per day, set a minimum number of hours between kept versions, filter by file name, or only delete versions older than a date.
- To see what would be removed before committing, run the same settings from Reports as a Version Trimming Report or Bulk Version Trimming Report, which changes nothing.
- Click Execute Trimmer (or Trim Sites in the bulk tool) and monitor progress.
For tenants that have never trimmed, version history is often the largest share of storage; the storage report's "Amount saved if trimmed" column tells you how much before you start. See the dedicated version trimming guide for a deeper walkthrough including library-level targeting.
Step 3: Compress Oversized Images
Images uploaded directly to SharePoint - product photos, site banners, scanned pages, presentation exports - are often uncompressed or only lightly compressed. A single high-resolution scan saved as an image can run to 20 MB. A folder of 500 such files represents 10 GB that can often be halved with no visible quality loss.
ShareMaster's Image Reducer scans a library for .jpg, .jpeg, .png, .gif and .tiff images above a size threshold you set, then re-encodes them as JPEG at the quality you choose. It replaces each file in place, keeping the filename and URL. Users rarely notice any quality difference for document-quality images.
It is not version-neutral: once a smaller image is uploaded, the tool deletes that image's previous versions, so the originals survive only if you tick the option to keep a full-size copy on your hard drive. Do not run it in libraries under a retention policy or legal hold, and leave out PNG logos and graphics that rely on transparency, because every reduced image is written back as JPEG data.
Step 4: Remove Empty Folders
Empty folders are a minor storage item on their own, but they add visible clutter, trigger sync client warnings, and slow down admin scripts that iterate library contents. Over years of migration activity and department reorganisations, empty folder trees accumulate quickly and silently.
ShareMaster's Empty Folder Remover works through a library or folder you pick, recursively, and sends every folder with no files and no subfolders to the recycle bin. There is no preview list, so if some folders are intentionally kept empty as structural placeholders, use its optional date to exclude folders modified after it, or point it at a narrower folder.
Step 5: Clear the Recycle Bin
Items in the first-stage SharePoint recycle bin still count against your storage quota. In a large, active tenant those bins can hold many gigabytes of data that nobody will ever restore. The bin operates in two stages:
- First-stage (site recycle bin): Visible to users within each site. Items sit here for up to 93 days from the deletion date, and they count against the site's storage.
- Second-stage (site collection recycle bin): Items cleared from the first-stage bin move here for the remainder of the 93-day window. Only site collection admins can see this stage, and apart from deleted subsites it does not count against quota.
Emptying the first stage is what frees quota, and it still leaves the items restorable from the second stage. Site collection admins do this from each site's own recycle bin page, one site at a time. Doing that across hundreds of site collections requires either a PowerShell loop or a tool that targets multiple collections at once.
ShareMaster's Recycle Master clears recycle bins across as many site collections as you tick, in a single operation, first stage and optionally second (this needs the SharePoint Administrator role). Where you want to look before you clear, it also filters a site's bin by deleted date, file type, original location or deleted-by user, one site collection at a time, so you can pull back anything a user still needs first.
Putting It All Together
| Step | Typical Storage Impact | Risk | ShareMaster Tool |
|---|---|---|---|
| Trim version history | Often the largest saving | Low (check holds first) | Space Master - Version Trimmer |
| Compress images | 5-20% (image-heavy tenants) | Low (removes old versions of reduced images; keep the local copy) | Space Master - Image Reducer |
| Remove empty folders | Negligible storage, reduces clutter | Very low | Space Master - Empty Folder Remover |
| Clear recycle bin | 5-15% (varies by tenant activity) | Low (review before clearing) | Recycle Master |
| Bulk delete unwanted files | Varies | Medium (permanent unless Send to recycling bin is ticked) | Space Master - Bulk Delete |
Frequently Asked Questions
Does clearing the SharePoint recycle bin free storage immediately?
Emptying the first-stage recycle bin is what frees quota. Microsoft counts the first-stage bin against a site's storage but not the second-stage bin, so items stop counting once they move to the second stage. Deleting them from the second stage frees nothing further, except deleted subsites, which count until they are purged. The site's reported storage figure can take a while to refresh.
How many versions does SharePoint Online keep by default?
By default, SharePoint Online document libraries retain up to 500 major versions per file, unless your organisation or site has set different version history limits, such as the automatic setting. Minor versions are kept too where a library has them turned on. Each version counts separately against your tenant storage quota. See the SharePoint versioning defaults reference for library-type-specific settings.
Can I reduce SharePoint storage without permanently deleting files?
Image compression keeps every file. ShareMaster's Image Reducer replaces large image files with smaller compressed versions in place, keeping the filename and URL, but it deletes the previous versions of each image it reduces, so keep the local copy of the originals it offers. Version trimming does remove old versions, but those are typically safe to delete unless a legal or compliance hold is in place. Check with your compliance team before trimming any library under retention policy.
What is the SharePoint Online tenant storage quota formula?
Your tenant receives 1 TB of base storage plus 10 GB per licensed Microsoft 365 user. A 200-user organisation gets 3 TB total (1 TB + 2 TB) pooled across all site collections. Individual site collections can be capped below the pooled total by a SharePoint admin.
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